A brake control system is generally utilized for engaging and disengaging a service brake and a parking brake associated with a vehicle. Service brakes are utilized to stop a moving vehicle slowly. Parking brakes are latching brakes utilized primarily for preventing the vehicle from moving from a parked position. Parking brakes may also be utilized in an emergency situation to slow the moving vehicle when the service brakes have failed to provide a redundant brake circuit. EPB (Electrical Parking Brake) systems include an EPB mechanism for applying an actuating force to the parking brake associated with the vehicle. The EPB mechanism is generally actuated in response to the operation of a push/pull hand lever located on a vehicle dash panel within a cab of the vehicle.
The vehicle may include more than one push/pull knob, depending upon whether or not an additional control is available for the parking brakes, such as in the case of a trailer attached to the vehicle. The push/pull knob is generally connected to an air valve, which controls the flow of air to the parking brake. In general, when the operator pushes the valve in, air pressure can be provided to the parking brake and the brake then released, thereby allowing the vehicle to move. In order to apply the brake, the operator pulls the push/pull knob and the air pressure is then removed from the parking brake, thereby allowing the brake to be engaged. When the knob is pushed in, the air pressure acts to engage the knob and maintain the knob in the pushed position.
Such push/pull knobs and air valves can be plumbed with air lines that are capable of being routed to and from the push/pull knobs located in the dash panel of the vehicle. Hence, the dash panel must be relatively large to accommodate such air lines. Additionally, such air lines are costly to install and to service because of the restricted space behind the dash panel. Furthermore, maintenance can be difficult in the case, for example, where an air leak is present in the valve or associated hoses. Such an air leak can be difficult to find and repair due to the restricted space of the dash panel.
Based on the foregoing, it is believed that a need exists for an improved electric parking brake control system for automatically controlling parking brakes. A need also exists for an improved electric brake switch with time delay capabilities for preventing inadvertent application of an electric parking brake, as described in greater detail herein.